Echocardiograms performed at baseline and follow‐up were exported from Synapse Cardiovascular (FUJIFILM Medical Systems) in DICOM (Digital Imaging and Communications in Medicine) format and analyzed using Image‐Arena v4 (TomTec Imaging Systems), a vendor‐neutral imaging platform.
Measurements were obtained for proximal RVOT dimensions in both PLAX and parasternal short‐axis (PSAX) views during end‐diastole, as shown in Figure1 . RV‐FAC was assessed as described in the TFC4 as the percentage of RV area decrease between diastole and systole obtained on apical imaging. All echocardiograms were analyzed by a single operator (S.W.) to exclude interobserver variability, and measurements were performed blinded to clinical data.
Structural progression was assessed by calculating the change in these echocardiographic parameters between the baseline and follow‐up studies. These changes were normalized as yearly and 5‐year rates of change, and patients were subsequently grouped into quartiles by rate of change. Patients were characterized as progressors or nonprogressors for each variable; progression was defined as an increase in PSAX RVOT size, increase in PLAX RVOT size, and decrease in RV‐FAC.
Measurements were obtained for proximal RVOT dimensions in both PLAX and parasternal short‐axis (PSAX) views during end‐diastole, as shown in Figure
Structural progression was assessed by calculating the change in these echocardiographic parameters between the baseline and follow‐up studies. These changes were normalized as yearly and 5‐year rates of change, and patients were subsequently grouped into quartiles by rate of change. Patients were characterized as progressors or nonprogressors for each variable; progression was defined as an increase in PSAX RVOT size, increase in PLAX RVOT size, and decrease in RV‐FAC.